Development and Evaluation of an Indigenous Natural Corrosion Inhibitor for Steel in Cementitious Systems.

This research developed and evaluated the corrosion-inhibiting efficiency of a natural inhibitor prepared from a bamboo tree [referred to as bamboo leaf extract (BLE)]. The corrosion behavior of steel in BLE-admixed cementitious systems was examined using dynamic-polarization tests and salt-fog tests. The effect of the addition of BLE on the workability and compressive strength of cementitious systems was studied using flow-table and compression tests on mortars. Increased concentration of BLE and the preimmersion period of steel in BLE-admixed pore solution resulted in the increase of corrosion potentials and the reduction of corrosion currents. Furthermore, the addition of BLE improved the workability and compressive strength of mortars, and the mass loss of steel in BLE-admixed mortar was observed to be less than that in the control (BLE-free) specimens. The inhibitor's adsorption on the steel followed the Langmuir isotherm model, suggesting the formation of a protective layer at the steel–electrolyte interface, and accordingly, a 99% reduction of the corrosion current was achieved by preimmersing the steel in simulated concrete pore solution containing 700 ppm BLE for 7 days. [ABSTRACT FROM AUTHOR]